Suggested Immobilization Test (SIT) and Forced Immobilization Test (FIT)
Diagnostic tests for the treatment of sleep disorders

It is used in the diagnosis of Restless Legs Syndrome.

They are used to corroborate the sensation of restlessness in the legs and to quantify the periodic movements of the extremities in restless legs syndrome during wakefulness. In the first, the patient sits or lies motionless, and in the second, the legs are immobilized to the stretcher while muscle activity is recorded in both tibialis anterior for one hour.

A TIS or TIF index is calculated, useful not only as a diagnostic tool, but also for treatment control. It can be used several times a day to measure circadian variations in motor restlessness and does not require an all-night polygraph recording.